This is a build for an Elementalist, Lightning Tendrils Cast While Channeling Arc for the clear, that can apply 50% shock to every monster in the game, even endgame bosses. The mechanics will be developed later in this guide. In addition to this, this build introduce in detail the issues that new player should pay attention to when leveling in delve.

Pros & Cons

Pros

• + Fast clear speed.
• + Extremely fun.
• + Elementalist.
• + Insane damage on bosses.
• + Party play friendly.
• + Viable for 95% of the content.

Cons

• - Squishy on a full damage setup, so not HC viable unless you change the passive tree to a more defensive one.
• - You need Uber Lab for a fully functional build.

Skill Tree

Ascendancy

Beacon of Ruin -> Mastermind of Discord 

Bandits

Help Alira

Pantheon

Major: Soul of the Brine King
Minor: Soul of Tukohama

Passive Tree

Gems Setup

Gems will be sorted by order of importance.

Main Damage setup 

Lightning Tendrils - Cast While Channeling - Vaal Arc or Arc (Shock Nova / Ball Lightning) - Controlled Destruction - Hypothermia (5L) - Inc. Area of Effect - (6L)

Try to get Vaal Arc as soon as possible, it's an insane boost of damage

When fighting bosses, use Elemental Focus instead of Inc. Area of Effect.

Hypotermia can be changed to Lightning Penetration if you have no source of added flat cold damage and don't want to rely on the Chilling Conflux.

Auras 

Herald of Thunder - Curse on Hit - Conductivity/Warlord's Mark

Wrath in the Essence Worm

Quality for Herald of Thunder is important as it gives up to 15% (even 17% with 23% quality corruption) GLOBAL increased lightning damage.

Orb of Storms setup 

Orb of Storm - Arcane Surge (lv7) - Power Charge on Critical - Unbound Ailments

Cast this often to keep the Arcane Surge buff which is an importan source of damage. 

With Unbound Ailments, Orb of Storms can apply higher shocks and chills which let us use Elemental Focus vs bosses in our main setup . 

It also increase the mana cost of OoS so we can have a higher lvl Arcane Surge.

Lightning Warp 

Lightning Warp - Faster Casting - Less Duration - Swift Affliction

We want a fast movement skill and with all our cast speed. LW to be a good choice. Plus it's a lightning spell so it fits thematically. And if you have the Innocence MTX, everyone will be jealous of your style.

CWDT setup 

Cast when Damage Taken (lvl 8) - Immortal Call (lvl 10) - Increased Duration

- OR -

Cast When Damage Taken (lvl 1) - Tempest Shield (lvl 7) - Ball Lightning (lvl 4)

The damage from Ball Lightning and Tempest Shield will heal us a bit and will also help to recover our mana by shocking enemies.

Golem 

Lightning Golem

For those who want to use a golem, this one is actually pretty good. He gives Cast speed that is good for both our dps and mobility. Also, the helmet enchant with 150% increase buff is incredibly good.

If you want and have the sockets for it, you can link it with gems like Minion Life, Blind, Culling Strike

Leveling Guide (new player)

If it's your first build of the league :

It's a general leveling guide, you are not forced to pick the exact gems or to follow every step, it's just how I would do it.

Do every quest that gives a skill point plus the first Nessa quest to get the Quicksilver Flask.

Act 1

- After entering Lioney's Watch -> Pick Freeze Pulse link it with Arcane surge and buy Fire Trap. Don't level this gem past level 7/8. Lightning Tendril mana cost is too high at lower level so we will pick it up later.

- After entering Mud Flats -> Capture 3 Rhoas plus the Rhoa mini-boss Oozeback Bloom, talk to Einhar to enter your menagerie and craft boots with guaranteed 10% movement speed.

- After entering The Submerged Passage -> You can go back to town and pick up orb of storm.

- After entering The Climb -> Capture 3 normal Goatman plus the mini-boss. In the menagerie craft a Quicksliver Flask of Adrenaline (20 to 30% additional movement speed).

- After killing Brutus -> Pick Clarity and buy Flame Dash. We can now sustain Lightning Tendrils so pick it up and swap it in instead of Freezing Pulse. Pick Added Lightning and link it.
You can buy Multitrap and link it with Fire Trap if you have 2 green links.

- After entering The Cavern of Wrath -> Pick Arc and socket it somewhere in your gear or weapon swap to level it. You can also use it instead of Lightning Tendrils.

Act 2

- After completing the Chamber of Sin quest -> Pick up Herald of Thunder.

- Go kill Kraityn -> Go kill Oak and pick the Waypoint of the zone -> Go help Alira.

- After killing The Weaver - > Pick Concentrated Effect and socket it in place of Arcane Surge. Link Arcane Surge with Orb of Storm. If you have a 4 link, buy Faster Casting. You should drop Fire Trap if you feel like having enough damage.

Act3

- After getting the Sewers keys -> Pick Conductivity. You can buy Wrath to level but i would not recommend to use it yet.

- After killing General Gravicius -> Pick Ball Lightning. Same as Arc, you can use it instead of Lightning Tendrils.

Act4

- After unlocking The Mines door -> Pick Lightning Golem.

- After entering The Belly of the Beast -> Pick Increased Area of Effect, buy Cast while Channelling. You should have a 4 link with 4 blue sockets at this point, socket Lightning Tendrils - CwC - Arc/Ball Lightning - Concentrated Effect.

From this point, try to get closer to the gem setup written in the Gem Links section as you progress trough acts !

For the lab, try to do it around the level of the zone in lab (33, 68 and 75) if you fing yourself too squishy just wait, it's not a big deal to run it a bit overleveled.

If you find an Alchemy Orb or a Chaos Orb while leveling, you should invest it instantly in some cheap leveling uniques such as :

• Axiom Perpetuum for the weapon

• Nomic's Storm or Wanderlust for boots

• Lochtonial Caress for gloves

Sell them once you reach around level 62 so you can start to buy items listed in the Budget section just below.

Gear (budget)

Weapon

Singularity

• - High Flat Lightning damage to spells
• - High cast speed
• - Mana cost reduction
• - Hinder close ennemies (-25% movement speed)
• - (60-80)% increased Damage with Hits and Ailments against Hindered Enemies 

Gloves 

If you don't have a 5L Inpulsa yet, don't use a Tabula, try :

Kalisa's Grace

• - High Life roll
• - Pseudo 5L with Faster Casting
• - Gain +2% to Critical Strike Chance for 2 seconds when you Spend a total of 800 Mana

That's BASE crit chance so it's really good dps boost. It will be up really often because Lightning tendril with high cast rate cost quite a bit.

Rings 

Until you can afford Valako's Sign and Essence Worm, any ring with these stats will do the trick.

• - Life
• - Res
• - Mana

Tough you will have to adjust your setup a bit. You should not run Wrath until you have Essence Worm or it will reserve too much mana and your Mind Over Matter will be useless.

Also you should run Warlord's Mark instead of Conductivity until you get Valako's Sign to keep the life leech.

Amulet 

Choir of the Storm can be intimidating in price so, until you save enough money for that awesome upgrade, you can use any rare amulet with these stats (by order of importance) :

• - Critical Strike Chance
• - Critical Strike Multiplier
• - Lightning Spell damage
• - Life
• - Mana
• - Dex

You should go full offensive on the amulet since it's the slot where you can get the most dmg after the weapons slots. Dexterity is nice to save a point in the tree.

That should not cost more than 5-10 Chaos Orbs depending on the rolls you chose and you will be able to farm low tier Red maps with it

Enchantments

Helmet

• - Arc Chains an additional 3 times
• - 40% increased Arc Damage
• - Arc deals 12% increased Damage for each time it has Chained
• - 40% increased Lightning Tendrils Damage
• - 60% increased Lightning Tendrils Critical Strike Chance 
• - 150% increased Effect of the Buff granted by your Lightning Golems 

Boots

• - Adds 1 to 160 Lightning Damage if you haven't Killed Recently
• - Damage Penetrates 10% of Enemy Elemental Resistances if you haven't Killed Recently
• - 16% increased Attack and Cast Speed if you've Killed Recently
• - Regenerate 2% of Life and Mana per second if you were Hit Recently

Gloves

• - Trigger Decree of Reflection when Hit, it spawns a double that can draw aggro for a short time.
• - Trigger Decree of Light when you take a Critical Strike, it creates consecrated ground under yourself for a bit of hp regeneration.

Expectations